I have just received the scheduling of the PSL self work for tomorrow. Gautam and I agreed that if it is needed I will shut the laser off and cover the hole table with plastic.

Measurements for good fit were made. The new shelf will be installed on next Tuesday at 2pm

The reference cavity ion pump is in the way  so the cavity will be moved 5" westward. The shelf height space will be 10"  Under shelf working height 18" to optical table.

While moving the RefCav to facilitate the PSL shelf install, I bumped the power cable to the AOM driver. I will re-solder it in the evening after the shelf installation. PMC and IMC have been re-locked. Judging by the PMC refl camera image, I may also have bumped the camera as the REFL spot is now a little shifted. The fact that the IMC re-locked readily suggests that the input pointing can't have changed significantly because of the RefCav move.

[ Johannes, Rana, Mark and Steve ]

On the second trial the shelf was installed. Plastic cover removed. South end door put back on and 2W Inno turned on.

Shelf 10 " below the existing one:   92" x 30" x 3/4" melamine (or MDF) covered with white Formica.  200 lbs it's max load. Working distance to top of the table 18"

Johannes informed me that he touched up the PMC REFL camera alignment. I am holding off on re-soldering the AOM driver power as I could use another pair of hands getting the power cable disentangled and removed from the 1X2 rack rails, so that I can bring it out to the lab and solder it back on.

Is anyone aware of a more robust connector solution for the type of power pins we have on the AOM driver?

Till RIN measurement noise eater is off on 2W laser. The inno 1W  has no noise eater.

2010 power v current table is below.

I think we can scrap the 126MOPA channels since they're associated with the Lightwave NPRO and MOPA. We should add the channels that we need for monitoring the Innolight NPRO from the d-sub connector on its controller.

Caution: Because of this work and my negligence, the RF output of the main Marconi for the IFO modulation is probably off. The amplifier (freq gen. box) was turned on. Therefore, we need to turn the Marconi on for the IFO locking.

I worked on my EOM m easurement using the beat setup. As there was the aux injection electronics, I performed my measurement having tried not to disturb the aux setup. The aux Marconi, the splitted PD output, and an open channel of the oscilloscope were used for my purpose. I have brought the RF spectrum analyzer from the control room. I think I have restored all the electronics back as before. I have re-aligned the beat setup after the EOM removed. Note that the aux NPRO, which had been on, was turned off to save the remaining life of the laser diode.

The 3IFO EOM was formerly tuned as the H2 EOM, so the resonant frequencies are different from the nominal aLIGO ones.

PORT1: 8.628MHz / 101 +/- 6 mrad_pk/V_pk
PORT2: 24.082MHz / 41.2 +/- 0.7 mrad_pk/V_pk
PORT3: 43.332MHz / 62.2 +/- 4 mrad_pk/V_pk

9MHz modulation is about x2.4 better than the one installed at LHO.
24MHz modulation is about x14 better. (This is OK as the new 24MHz is not configured to be resonant.)
45MHz modulation is about x1.4 better.
 

The marconi RF output was turned on and thus the RF generator condition was restored to the nominal state on Friday 11th.

The AUX laser is down to 5.4 mW output power

What's worse, because we wanted those fast switching times by the AOM for ringdowns, I made the beam really small, which

1. came with a severe tradeoff against conversion efficiency. I tried to squeeze the last out of it today, but there's only about 1.3 mW of diffracted light in the first order that reaches the fiber, with higher diffraction orders already visible.
2. produced a very elliptical mode which was difficult to match into the fiber. Gautam and I measured 600 uW coming out of the fiber on the AS table. This per se is enough for the SRC spectroscopy demonstration, but with the current setup of the drive electronics there's no amplitude modulation of the deflected beam.

When going though the labs with Koji last week I discovered a stash of modulators in the Crackle lab. Among them there's an 80 MHz AOM with compact driver that had a modulation bandwidth of 30MHz. The fall time with this one should be around 100ns, and since the arm cavities have linewidths of ~10kHz their ringdown times are a few microseconds, so that would be sufficient. I suggest we swap this or a similar one in for the current one, make the beam larger, and redo the fiber modematching. That way we may get ~3mW onto the AS table.

I think I want to use AS110 for the ringdowns, so in the next couple days I'll look into its noise to get a better idea about what power we need for the arm ringdowns.

I brought the NPRO from the Crackle experiment over to the 40m Lab and set it up on the PSL table to replace the slowly dying AUX laser. I also brought along a Faraday isolator, broadband EOM, and an ISOMET AOM with driver electronics from the optics storage in the Crackle Lab.

This laser is a much newer model, made in 2008, and still has all its mojo, but we should probably keep up the practice of turning it off when it's not going to be used for a while. I measured 320 mW leaving the laser, and 299mW of that going through the Faraday isolator, whose Brewster-angle polarizer I had to clean because they were a little dusty. While the laser output is going strong, the controller displays a power output of only 10 mW, which makes me think that the power monitoring PD is busted. This is a completely different failure mode from what we've seen with the other NPROs that we can hopefully get repaired at some point, particularly because the laser is newer, but for now it's installed on the PSL table. This likely means that the noise eater isn't working on this unit either, for different reasons, but at least we have plenty of optical power.

The setup is very similar to before, with the addition of a Faraday isolator and a broadband EOM, in case we decide to get more bandwidth in the PLL. I changed the Crystal Technologies 3200-113 200 MHz AOM for an ISOMET 80 MHz AOM with RF driver from the Crackle lab's optics storage and sized the AUX beam to a diameter of 200 micron. I couldn't locate an appropriate heat sink for the driver, which is still in factory condiction, but since the PSL AOM also runs on 80MHz I used that one instead. The two AOMs saturate at different RF powers, so care must be taken to not drive the AUX AOM too high. At 600 mV input to the driver the deflection into the first order was maximal at 73 % of the input power, with the second order beam and the first order on the other side cleary visible.

In order to speed things up I didn't spend too much time on mode-matching, but the advantage of the fiber setup is that we can always improve later if need be without affecting things downstream. I coupled the first order beam into the fiber to the AS table with 58% efficiency, and restored the beat with the PSL laser on the NewFocus 1611. The contrast there is only about 20%, netting a -20 dBm beat note. This is only a marginal improvement from before, so the PLL will work as usual, but if we get the visibility up a little in the future we won't need to amplify the PD signal for the PLL anymore.

Some more things I wanted to do but didn't get to today are

• Measure intensity noise of aux laser
• Measure rise and fall times of new AOM
• Get PLL back up and running
• Place 90/10 beamsplitter in AS path and couple IFO output into fiber (= couple fiber output into IFO)

I'll resume this work tomorrow. I turned the aux laser and the AOM driver input off. For the PSL beat the AOM drive is not needed, and the power in the optical fiber should not exceed 100 mW, so the offset voltage to the AOM RF driver has to remain below 300 mV.

> While the laser output is going strong, the controller displays a power output of only 10 mW, which makes me think that the power monitoring PD is busted.

NPRO internal power monitor often shows smaller value than the actual due to a broken PD or misalignment. I don't think we need to fix it.

STEVE: Aux Lightwave M126-1064-200, sn259 [July 2009] 1.76A, ADJ 9,  9mW on it's display should not mislead you. It's output  320mW

We have the appropriate heatsink - I'd like to minimize interference with the main beam wherever possible.

If damage to the fiber is a concern, I think it's better to use a PBS + waveplate to attenuate the power going into the fiber. When the AOM switching is hooked up to CDS, it's easy to imagine a wrong button being pressed or a wrong value being typed in.

It would probably also be good to have a pickoff monitor for the NPRO DC power so that we can confirm its health (in the short run, we can hijack a PSL Acromag channel for this purpose, as we now do for FSS_RMTEMP). I don't know that we need an EOM for the PLL, as in order to get that going, we probably need some fast electronics for the EOM path, like an FSS box. 

STEVE: I ordered the right heatsink for the acousto after Koji pointed out that the vertical fins are 20% more efficient. Why? Because hot air rises. It will be here in 3-4 days.

[johannes, gautam]

1. Johannes aligned the single bounce off the ITM into the AUX fiber on the AS table, and also the AUX beam into the fiber on the PSL table.
   • Mode matching isn't spectaular anywhere in this chain.
   • But we have 2.6mW of light going into the SRM with the AOM deflection into the 1st order beam (which is what we send into the IFO) maximum.
2. We set up some remote capabilities for the PLL and Marconi frequency (=PLL setpoint) control.
3. Motivation was to try and lock DRMI, and look for some resonance of the AUX beam in the SRC.
   • We soon realized this was a way too lofty goal.
   • So we decided to try the simpler system of PRMI locked on carrier.
   • We were successfully able to sweep the Marconi setpoint in up to 20kHz steps (although we can only move the setpoint in one direction, not sure I know why now).
   • Then we decided to look for resonances of the AUX beam in the arm cavity.
   • Still no cigar
     
4. Plus points:
   • PLL can be reliably locked remotely.
   • Marconi freq. can be swept deterministically remotely.
5. Tomorrow:
   • Fix polarization issues. There is some low freq drift (~5min period) of the power incident on the fiber on the PSL table which we don't understand.
   • Verify MM into IFO and also into fiber at PSL table.
   • Do mode spectroscopy.

I was wondering why the PMC modulation sidebands are showing up on the control room analyzer with ~6dB difference in amplitude. Then I realized that it is reasonable for the cabling to have 6dB higher loss at 80 MHz compared to 20 MHz.

I worked a bit on the PSL table today

It isn't clear to me in the drawing where the Agilent is during this measurement. Over 40m of cabling, the loss of signal can be a few dB, and considering we don't have a whole lot of signal in the first place, it may be better to send the stronger RF signal (i.e. Marconi pickoff) over the long cable rather than the weak beat signal from the Transmission photodiode. 

Among the things that we hadn't taken care of yesterday before beginning to look for transmission signals were the polarization of the AUX beam on the AS table and optimizing the PLL feedback. The AUX beam is s-polarized on the PSL table (choice due to availablility of mirrors), and I added a half waveplate in front of the fiber to match it's axes. I placed another half-waveplate at the fiber output and send the reflection port of a PBS cube onto a PDA1CS photodetector. By alternatingly turning the waveplates I minimized the reflected light, giving strongly p-polarized light on the AS table for best results when interfering with the IFO beam. I wiggled the fiber and found no strong dependency of the output polarization on fiber bending. Attachment 2 shows the current layout.

The beat signal between AUX and PSL table is at -20dBm, and I adjusted the PLL gain and PI-corner to get reliable locking behavior. I think it's a good idea to keep the AUX beam on the AS table blocked while it's not in use, and only unblock it when it is phaselocked to avoid a rogue beam with no fixed phase relation to the PSL in the IFO.I blocked the beam after completing this work today.

I used the signal chain that Keerthana, Koji, and I set up yesterday to look for mode flashed of the AUX light in the YARM using the RF beat with the PSL carrier in transmission. To align the AUX beam to the arm the following steps were performed:

1. Using a spectrum analyzer to look at the RF power at the target frequency between frequency-shifted AUX beam and PSL carrier on AS110, align the beam using the mirror pair closest to the fiber coupler for maximum signal.
2. Initiate a sweep of the PLL LO frequency sourced by the Marconi using GPIB scripts over about 1 FSR. A strong peak was visible at ~31.76 MHz offset frequency
3. Tune and hold LO frequency (in this case at 48.2526 MHz) such that AUX beam resonates in the arm. Optimize alignment by maximizing RF signal on PD in transmission.

This was followed by a sweep over two full FSRs. Attachment #1 shows the trace recorded by the AG4395 using the max data hold setting during the sweep. Essentially the beat between AUX and PSL carrier traced out the arm's transmission curve. At minimum transmission there was still a ~82dB beat on the transmission PD visible.

The YEND QPD is currently blocked and sees no light.

Yesterday, I moved the following optics:

1. Lens in front of AS110 PD.
2. BS splitting light between AS110 and AS55.

After moving these components around a bit, I locked them down once I was happy that the beam was pretty well centered on both of them, and also on AS110 and AS55 (measured using O'scope with single bounce from one ITM, other optics misaligned).

The beam was close to clipping on the lens mentioned in #1, probably because this wasn't checked when the 90-10 BS was installed for the AUX laser. Furthermore, I believe we are losing more than 10% of the light due to this BS. The ASDC (which is derived from AS55 PD) level is down at ~110cts as the Michelson is fringing, while it used to be ~200 cts. I will update with a power measurement shortly. But I think we should move ahead with the plan to combine the beam into the IFO's AS mode as discussed at the meeting last week.

Unrelated to this work, but c1psl and c1iscaux were keyed. 

ASDC has something weird going on with it - my main goal yesterday was to calibrate the actuators of ITMX, ITMY and BS using the Michelson. But with the Michelson locked on a dark fringe, the ASDC level changed by up to 50 counts seemingly randomly (bright fringe was ~1000 cts, I had upped the whitening gain to +21dB), even though the CCD remained clearly dark throughout. Not sure if the problem is in the readout electronics or in the PD itself.

Is the 10% specified for P-Pol or for UNP? I contacted CVI about beamsplitters, since their website doesn't list a BS1-1064-90-... option on the website. They say a R=90% beamsplitter would be a custom job. The closest stock item they got is BS1-1064-95-2025-45UNP specified at R=95% for UNPolarized beams. They were kind enough to sent me the measured transmission curves for a recent lot of these, which is attached was uploaded to the wiki [Elog Police K: NO PROPRIETARY DOCUMENTS ON THE ELOG, which is public. Put it on our wiki and put the link here]. The figure is not labeled, but according to the contact Red is S-Pol and Blue is P-Pol, which means that this one actually has R=~90% for P, pretty much what we want. We'll need to buy two of these to make the swap in the setup.

Back to your original point: There's only a BS1-1064-10-2025-45UNP on the website, so unless we got these as custom items, the R for P-Pol is probably NOT actually 10%, just somewhere between 0% and 20%

Of course, many (but no all) of the optics were custom-ordered back in ~2000.

4  std cataloge item fused silica  BS1-1064-95-2025-45UNP 

ordered today. They will arrive no later than July 13, 2018

In order to use the 0th-order deflection beam from the AOM for cavity mode scans, I've coaligned this beam to the existing mode-matching/launch optics set up for the 1st-order beam.

Instead of being dumped, the 0th-order beam is now steered by two 45-degree mirrors into the existing beam path. The second mirror is on a flip mount so that we can quickly switch between 0th-order/1st-order injections. None of the existing optics were touched, so the 1st-order beam alignment should still be undisturbed.

Currently the 0th-order beam is being injected into the IFO. After attenuating so as to not exceed 100 mW incident on the fiber, approximately 50 mW of power reaches the AS table. That coupling efficiency is similar to what we have with the 1st-order beam. With the Y-arm cavity locked and the AUX PLL locked at RF offset = 47.60 MHz (an Y-arm FSR), I observed a -50 dBm beat note at Y-end transmission.

I was preparing for the aLIGO EOM measuement to be carried out tomorrow afternoon.

I did a few modifications to the PLL setup.

• The freq mixier in the PLL setup was replaced with ZP3 (level 7) from ZAD-6
• The PLL gain was reduced from 3.10 to 2.80 to prevent servo oscillation
• The main PSL marconi is connected to the PLL mixier and providing fixed 200MHz 8dBm.
• The main PSL modulation is off.

Tomorrow I am going to modulate the EOM with the AUX Marconi via an amplifier (probably)

Automated scripts (AGinit.py and AGmeas.py) are in /users/koji/scripts

I will revert the setup once the measurement is done tomorrow.

Rich and I worked on the EOM measurement. After the measurement, the setup was reverted to the nominal state

• AUX PLL mixer was restored to ZAD-6
• The PLL gain was restored to 3.10
• The main PSL marconi is connected to the freq generator again. Using the beat note, I've confirmed that the modulations are applied on the beam.
• The PSL HEPA was reduced from 100 to 30.

The main laser went off when PSL doors were opened-closed. It was turned back on and the PSL is locked.

I tried to plot a long trend MC Transmitted today. I could not get farther than 2017 Aug 4

Attached is my phone recording of what it sounds like right now in the PSL enclosure - not good for frequency noise measurement! The culprit is the little PC fan that is hacked onto the back of the Innolight controller. 

1. Is this necessary?
2. If so, is it sufficient to replace this fan with one from our stock?

This thread: ELOG 10295

My interpretation of these ELOGs is that we did not have the replacement, and then I brought unknown fan from WB. At the same time, Steve ordered replacement fans which we found in the blue tower yesterday.
The next action is to replace the internal fan, I believe.

I could probably install the new fan if we have one.  Can you do without the laser for a while?

When I got back from lunch just now, I noticed that the PMC TRANS and REFL cameras were showing no spots. I went onto the PSL table, and saw that the NPRO was in fact turned off. I turned it back on.

The laser was definitely ON when I left for lunch around 130pm, and this happend around 140pm. Anjali says no one was in the lab in between. None of the FEs are dead, suggesting there wasn't a labwide power outage, and the EX and EY NPROs were not affected. I had pulled out the diagnostics connector logged by Acromag, I'm restoring it now in the hope we can get some more info on what exactly happened if this is a recurring event. So FSS_RMTEMP isn't working from now on. Sooner we get the PSL Acromag crate together, the better...

Happened again at ~730pm.

The NPRO diag channels don't really tell me what happened in a causal way, but the interlock channel seems suspicious. Why is the nominal value 0.04 V? From the manual, it looks like the TGUARD is an indication of deviations between the set temperature and actual diode laser temperature. Is it normal for it to be putting out 11V?

I'm not going to turn it on again right now while I ponder which of my hands I need to chop off.

After discussing with Koji, I turned the NPRO back on again, at ~4PM local time. I first dialled the injection current down to 0A. Then powered the control unit state to "ON". Then I ramped up the power by turning the front panel dial. Lasing started at 0.5A, and I saw no abrupt swings in the power (I used PMC REFL as a monitor, there were some mode flashes which are the dips seen in the power, and the x-axis is in units of time not pump current). PMC was relocked and IMC autolocker locked the IMC almost immediately.

Now we wait and watch I guess.

When dialing up the current, I went up to 2.01 A on the front panel display, which is what I remember it being. The label on the controller is from when the laser was still putting out 2W, and says the pump current should be 2.1 A. Anyhow, the MC transmission is ~7% lower now (14500 cts compared to the usual 15000-15500 cts), even after tweaking the PMC alignment to minimize PMC REFL. Potentially there is less power coming out of the NPRO. I will measure it at the window tomorrow with a power meter.

NPRO shutoff at ~1517  local time today afternoon. Again, not many clues from the NPRO diagnostics channel, but to my eye, the D1_POW channel shows the first variation from the "steady state", followed by the other channels. This is ~0.1 sec before the other channels register some change, so I don't know how much we can trust the synchronizaiton of the EPICS data streams. I won't turn it on again for now. I did check that the little fan on the back of the NPRO controller is still rotating.

gautam 10am 4/29: I also added a longer term trend of these diagnostic channels, no clear trends suggesting a fault are visible. The y-axis units for all plots are in Volts, and the data is sampled at 16 Hz.

It is noticed that one of the doors (door # 2 ) of the PSL table is broken. Attachement #1 shows the image

Gautam and I are removing the prototype Acromag chassis from the 1x4 rack to make room for the new c1susuax hardware. I shut down and disabled the modbusPSL service running on c1auxex, which serves the PSL diagnostic channels hosted by this chassis. The service will need to be restarted and reenabled once the chassis has been reinstalled elsewhere.

I turned the 2W NPRO back on again at ~4pm local time, dialing the injection current up from 0-2A in ~2 mins. I noticed today that the lasing only started at 1A, whereas just last week, it started lasing at 0.5A. After ~5 minutes of it being on, I measured 950 mW after the 11/55 MHz EOM on the PSL table. The power here was 1.06 W in January, so ~💯  mW lower now. 😮 

I found out today that the way the python FSS SLOW PID loop is scripted, if it runs into an EZCA error (due to the c1psl slow machine being dead), it doesn't handle this gracefully (it just gets stuck). I rebooted the crate for now and the MC autolcoker is running fine again. 

NPRO turned off again at ~8pm local time after Anjali was done with her data taking. I measured the power again, it was still 950mW, so at least the output power isn't degrading over 4 hours by an appreciable amount...

Per instructions from Coherent, I made the some changes to the NPRO settings. The value we were operating at is in the column labelled "Operating value", while that in the Innolight test datasheet is in the rightmost column. I changed the Xtal temp and pump current to the values Innolight tested them at (but not the diode temps as they were close and they require a screwdriver to adjust), and turned the laser on again at ~1245pm local time. The acromag channels are recording the diagnostic information.

update 2:30pm - looking at the trend, I saw that D2 TGuard channel was reporting 0V. This wasn't the case before. Suspecting a loose contact, I tightened the DSub connectors at the controller and Acromag box ends. Now it too reports ~10V, which according to the manual signals normal operation. So if one sees an abrupt change in this channel in the long trend since 1245pm, that's me re-seating the connector. According to the manual, an error state would be signalled by a negative voltage at this pin, up to -12V. Also, the Innolight manual says pin 13 of the diagnostics connector is indicating the "Interlock" state, but doesn't say what the "expected" voltage should be. The newer manual Coherent sent me has pin13 listed as "Do not use".

As we have seen in the last few weeks, the laser turned itself off after a few hours of running. So bypassing the lab interlock system / reverting laser crystal temperature to the value from Innolight's test datasheet did not fix the problem.

I do not understand why the "Interlock" and "TGUARD" channels come revert to their values when the laser was lasing a few minutes after the shutoff. Is this just an artefact of the way the diagnostics is set up, or is this telling us something about what is causing the shutoff?

1. Increased PSL HEPA Variac from 30 to 100% to get more airflow.
2. All of the TEC setpoints seem cold to me, so I increased the laser crystal temperature to 30.6 C
3. Adjusted the diode TEC setpoints individually to optimize the PMC REFL power (unlocked). DTEC A = 22.09 C, DTEC B = 21.04 C
4. locked PMC at 1900 PT; let's see how long it lasts.

My hunch is that the TECs are working too hard and can't offload the heat onto the heat sinks. As the diode's degrade, more of the electrical power is converted to heat in the diodes rather than 808 nm photons. So hopefully the increased airflow will help.

I tried to increase the DTEC setpoints, but that seems to detune them too far from the laser absorption band, so that's not very efficient for us. IN any case, if we end up changin the laser temperature, we'll have to adjust the ALS lasers to match, and that will be annoying.

The office area was very cold and the HVAC air flow stronger than usual. I changed the setpoint on the thermostat near Steve's desk from 71 to 73F at 1830 today.

This time, it stayed on for ~24 hours. I am not going to turn it on again today as the crane inspection is tomorrow and we plan to keep the VEA a laser safe area for speedy crane inspection.

But what is the next step? If these diode temps maximize the power output of the NPRO, then it isn't a good idea to raise the TEC setpoint futher, so should I just turn it on again with the same settings?

I did not turn the HEPA down on the PSL enclosure. I also turned off the NPROs at EX and EY so now all the four 1064nm lasers in the VEA are turned OFF (for crane inspection).

This evening I added a second ADC module to the prototype Acromag chassis. This chassis can now read out all the PSL diagnostic channels.

I configured the second ADC identically to the first ("ADC0"), and assigned it IP address 192.168.113.122. I confirmed it is visible on the martian network.

There was an existing but unused DB-15 feedthrough which I used for ADC1 channels 1-7. The eighth channel I left unwired, but there are slots available in the neighboring DB-25 feedthough, if that channel is needed in the future. The channel wiring assignments are as follows.

I tested all seven of these channels by applying a calibrated voltage source and measuring the response via the Windows Acromag software. All work and are correctly calibrated to better than 0.1%.

1. In anticipation of installing the new fan on the PSL, I disconencted the old fan and finally removed the bench power supply from the top shelf.
2. Moved said bench supply to under the south-west corner of the PSL table.
3. Installed temporary Acromag crate, now with two ADC cards, under the PSL table and hooked it up to the bench suppy (+15 VDC). Also ran an ethernet cable from 1X3 to the box on over head cable tray and connected it.
4. Brought other end of 25-pin D-sub cable used to monitor the NPRO diagnostics channels from 1X4/1X5 to the PSL table. Rolled the excess length up and cable tied it, the excess is sitting on top of the PSL enclosure. Key parts of the setup are shown in Attachments #1-3. This is not an ideal setup and is only meant to get us through to the install of the new c1psl/c1ioo Acromag crate.
5. Edited the modbus config file at /cvs/cds/caltech/target/c1psl2/npro_config.cmd to add Jon's new ADC card to the list.
6. Edited EPICS database file at /cvs/cds/caltech/target/c1psl2/psl.db to add entries for the C1:PSL-FSS_RMTEMP and C1:PSL-PMC_PMCTRANSPD channels.
7. Hooked up said channels to the physical ADC inputs via a DB15 cable and breakout board on the PSL table.
   CH0 --- FSS_RMTEMP (Pins 5/18 of the DB25 connector on the interface box to pins 1/9 of the Acromag DB15 connector)
   CH1 --- PMC TRANS (BNC cable from PD to pomona minigrabber to pins 2/10 of the Acromag DB15 connector)
   CH2-6 are unsued currently and are available via the DB15 breakout board shown in Attachment #3. CH7 is not connected at the time of writing
   The pin-out for the temperature sensor interface box may be found here. Restarted the modbus process. The channels are now being recorded, see Attachment #4, although checking the status of the modbus process, I get some error message, not sure what that's about.

So now we can monitor both the temperature of the enclosure (as reported by the sensor on the PSL table) and the NPRO diagnostics channels. The new fan for the controller has not been installed yet, due to us not having a good mounting solution for the new fans, all of which have a bigger footprint than the installed fan. But since the laser isn't running right now, this is probably okay.

I took a look at the error being encountered by the modbusPSL service. The problem is that the /run/modbusPSL.pid file is not being generated by procServ, even though the -p flag controlling this is correctly set. I don't know the reason for this, but it was also a problem on c1vac and c1susaux. The solution is to remove the custom kill command (ExecStop=...) and just allow systemd to stop it via its default internal kill method.

I used some double-sided tape to attach a San Ace 60 9S0612H4011 to the Innolight controller (Attachment #1). This particular fan is rated to run with up to 13.8V, but I'm using a +15V Sorensen output - at best, this shortens the lifespan of the fan, but I don't have a better solution for now. Then I turned the laser on again (~1040 local time), using the same settings Rana configured earlier in this thread. PMC was locked, and the IMC also could be locked but I closed the shutter for now while the laser frequency/intensity stabilizes after startup. The purpose is to facilitate completion of the pre-vent alignment checklist in prep for the planned vent tomorrow. PMC Trans reports 0.63 after alignment was optimized, which is ~15% lower than in Oct 2016.

To test the hypothesis that the fan replacement had any effect on the NPRO shutoff phenomena, I turned the HEPA on the PSL table down to the nominal 30% setting at ~10am.

Tomorrow I will revert the laser crystal temperature to whatever the nominal value was. If the NPRO runs in that configuration (i.e. the only change from March 2019 are the diode TEC setpoints and the new fan on the back of the controller), then hurray.

Today, Rana had me key the PSL crate.

1. Locating the rack: the crate is 1X1. This link provides details of the locations and functions of the racks.
2. Keying the crate: the key is located at the bottom of the rack (in this case). Keying it requires one to turn the key through 90 degrees (anti clockwise facing the rack) and back to to the original position.

Locking the PMC:

1. Accessing the medm screen for the PMC: open a new terminal and use the command sitemap. This should open up the sitemap medm screen. Click on the PSL button and then select C1PSL_PMC from the dropdown that is produced. This opens up a medm screen similar to that in Attachment #1.
2. The correct toggling: The keying of the crate sometimes scrambles the settings on the medm screen. Rana and I performed extensive toggling of the buttons and concluded that the combination in Attachment #1 ought to be the correct one.
3. Locking the PMC: The state of the PMC was deduced by observing CH01 on monitor 7. When not locked, there is no observable bright spot. At this point the "Input Offset (V)" slider is set to zero and the "Servo Gain Adjust (dB)" slider is set to minimum. To obtain lock, complete step 2 and then move the "DC Output Adjust (V)"  slider (at the bottom left on the screen) around rapidly while looking for a bright spot. On observing such a spot on the monitor, release the slider and quickly increase the "Servo Gain Adjust (dB)" slider to around 15 dB. Higher gain values produce a bright spot on CH02 as well which vanishes (almost) on decreasing the gain to the aforementioned value.

1. IMC would not lock. c1psl EPICS channels were unresponsive. I keyed the crate and went through the usual burtrestore/PMC-relocking dance.
2. While at 1X2, I decided to take this opportunity to clean up the AG4395 setup that has been setup there unused for several weeks now.
   • Unplugged the active probe connected via BNC-T connector to the mixer IF output.
   • Noticed that the active probe (S/N 2850J01450) did not have it's power connection connected. According to the manual, this is bad. I don't know if the probe is damaged or not.
   • Moved the AG4395 cart out of the way so that there is a little more room around 1X1/1X2.